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110 Cards in this Set
- Front
- Back
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Villi |
Studded finger-like projections that line the large folds in the lining of the small intestine where much of the absorption occurs. |
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microvilli |
Each epithelial cell of a villus has a apical surface with many microscopic projections that are exposed to the intestinal lumen |
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Purpose of folds, villi, and microvilli |
they increase the surface area for absorption in the small intestine. |
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Small intestine transport to liver (liver functions) |
regulations of blood-sugar levels deaminates amino acids excretes bile pigments synthesizes bile salts |
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Absorption of fats in the lumen |
triglyceride exposed on the surface of fat droplets are subject to enzymatic hydrolysis. The enzyme lipase breaks the triglycerides down to fatty acids and monoglycerides |
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Diffusion of fats into the epithelial cells |
monoglycerids and fatty acids are re-formed into triglycerides and triglycerides are incorporated into water-soluble globules called chylomicrons |
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chylomicrons leave epithelial cells |
They leave by exocytosis and enter lacteals, where they are carried away by the lymph and later pass into large veins. |
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Large intestine |
-end of alimentary canal -includes the colon, cecum, and rectum -small intestine connects to the large intestine at a T-shaped junction |
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colon |
One arm of the T that is 1.5 m long and leads to the rectum and anus completes the reabsorption of water that began in the small intestine |
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cecum |
important for fermenting ingested material humans have a relatively small one |
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appendix |
a finger like extension of the human cecum, has a minor role in immunity |
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feces |
left in the colon and moves along the colon by peristalsis . -mainly undigested fiber |
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rectum |
where the feces are stored until they can be eliminated -two sphincters, the inner one being involuntary and outer one being voluntary -strong contractions of the colon cause us to have to defecate |
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enteric divison |
dedicated to the digestive organs, regulates churning of the stomach and the release of gastric juices as well as peristalsis in the small and large intestine |
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endocrine system and digestion |
when food arrives at stomach, stretches stomach walls and triggers the release of gastrin. Gastrin circulates via the bloodstream back to the stomach, where it stimulates production of gastric juices |
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Chyme |
an acidic mix of partially digested food passes from the stomach to the duodenum. duodenum responds to amino acids or fatty acids in chyme by releasing the digestive hormones cholecystokinin (CCK) and secretin. |
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CCK |
stimulates the release of digestive enzymes from the pancreas and of bile from the gallbladder |
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Secretin |
stimulates the pancreas to relate bicarbonate which neutralizes chyme |
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Chyme rich in fats |
If rich in fats, the high levels of secretin and CCK released act on the stomach to inhibit peristalsis and secretion of gastric juices, thereby slowing digestion |
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insulin |
when blood glucose levels rise above the normal range, secretion of glucose triggers the uptake of glucose from the blood into the body cells, decreasing the blood glucose concentration |
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glucagon |
when blood glucose levels drop below the normal range, the secretion of glucagon promotes the release of glucose into the blood from energy stores, such as liver glycogen, increasing the blood glucose concentration. |
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hepatic portal vein |
a blood vessel that leads directly to the liver. from the liver, blood travels to the heart and then to other tissues or organs because this allows the liver to regulate the distribution of nutrients to the rest of the body and to remove toxic substances before going to the rest of the body |
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alpha cells |
make glucagon found in cell clusters called pancreatic islets |
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beta cells |
make insulin. cells in the the pancreatic islets |
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pancreas |
cells produce hormones, produce and secrete bicarbonate ions and the digestive enzymes active in the small intestine. |
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ghrelin |
secreted by the stomach wall, one of the signals that triggers feelings of hunger. |
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insulin in satiety center |
functions by suppressing appetite by acting on the brain |
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leptin |
produced by adipose tissue suppresses appetite |
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PYY |
secreted by the small intestine after meals, acts as an appetite suppressant that counters ghrelin |
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gastrovascular cavity |
body shape that puts an organism's cells in direct contact with the environment and allows them to live without a distinct circulatory system. Also functions in digestion. Fluid bathes both the inner and out tissue layers, causing the exchange of gases and other cellular waste. A flat body optimizes exchange by increasing the surface area and minimizing the diffusion distance |
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circulatory system |
made up of a circulatory fluid, a set of interconnecting vessels, and a muscular pump or heart. |
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heart |
powers circulation by using metabolic energy to elevate the circulatory fluids hydrostatic pressure or the pressure the fluid exerts on surrounding vessels. then fluid flows through the vessels back to the heart. |
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Transportation of fluid in a circulatory system |
connects the aqueous environment of the boyd cells to the organs that exchange gases, absorb nutrients, and dispose of wastes. |
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open circulatory system |
hemolymph or interstitial fluids bath body cells. Heart contraction pumps the hemolymph through the circulatory vessels into interconnected sinuses, spaces surrounding the organs. Within sinuses chemical exchange occurs between hemolymph and body cells. Relaxation of heart draws hemolymph back into pores. Body movements help to circulate hemolymph |
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closed circulatory system |
blood is confined to vessels. one or more hearts pump blood into large vessels that branch to smaller ones to organs. Chemical exchange occurs between the blood and interstitial fluids and between the interstitial fluid and body cells |
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advantage of open circulatory system |
less costly in terms of energy |
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advantage of closed circulatory system |
relatively high blood pressure that enables effective O2 and nutrients to the cells or larger and more active animals. Well suited to regulating the distribution of blood to different organs |
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cardiovascular system |
circulatory system of humans. Blood circulates to and from the heart through a network of vessels. |
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types of blood vessels |
arteries, veins, and capillaries |
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arteries |
carry blood from the heart to organs throughout the body |
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arterioles |
artery branches that convey blood to capillaries |
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capillaries |
microscopic vessels with very thin, porous walls |
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capillary beds |
networks of capillaries that infiltrate tissues, passing within a few cell diameters of every cell in the body. Across the thin walls, chemicals, including dissolved gases are exchanged by diffusion between the blood and interstitial fluid around the tissue cell |
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venules |
capillaries converge into venules |
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veins |
venules converge into veins that carry blood back to the heart |
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atrium |
chambers that receive blood entering the heart |
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ventricles |
chambers responsible for pumping blood out of the heart |
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Single circulation |
bony fish, rays, sharks heart consists of two chambers atria and ventricle blood passes through the heart once in each circuit blood enters heart and collects in atrium before transfer to the ventricle contraction of ventricle pumps blood to capillary bed in gills where a net diffusion of O2 into blood and CO2 out of blood. As blood leaves gills, capillaries converge into a vessel that carries oxygen-rich blood to capillary beds throughout body. Blood returns to heart |
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disadvantage of single-circulation |
blood leaves heart passes through two capillary beds before returning to heart. Blood pressure drops substantially and limits the rate of blood flow to rest of animal body. Swimming allows muscles to accelerate the pace of circulation |
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Double circulation |
pumps for two circuits are combined into the heart. having both pumps within a single heart simplifies the coordination of the pumping cycles. One pump (right side) delivers oxygen poor blood to the capillary beds of the gas exchange tissue, where there is movement of O2 into blood and CO2 out of blood. Then enters left side. Contraction of heart propels blood to capillary beds in organs and tissues in body. |
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systemic circuit |
part of the cardiovascular system which carries oxygenated blood away from heart to body and returns deoxygenated blood back to heart |
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pulmonary circuit |
part of the cardiovascular system that carries oxygenated blood away from the heart, to the lungs, and returns oxygenated blood back to heart |
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advantage of double circulation |
provides a vigorous flow of blood to brain, muscles and other organs because heart depressurizes blood destined for tissues after it passes through capillary beds of lungs or skin |
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stomata |
allow exchange of CO2 and O2 between surrounding air and the photosynthetic cells inside leaf. It also helps in water loss |
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guard cells |
regulate the opening and closing of the stomata |
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apoplastic route |
uptake of soil solution by hydrophilic walls of root hairs provide access to the apoplast. Water and minerals can then diffuse into the cortex along this matrix of walls and extracellular spaces |
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symplastic route |
minerals and water that cross the plasma membranes of root hairs can enter the symplast |
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transmembrane route |
as soil solution moves along the apoplast, some water and minerals are transported into the protoplasts of cells of the epidermis and cortex and then move inward via the symplast |
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endodermis (controlled entry to the vascular cylinder) |
within transverse and radial walls each endodermal cell is the casparian strip, a belt of waxy material that blocks the passage of water and dissolved miners. Only minerals already in the symplast or entering the pathway by crossing the plasma membrane of an endodermal cell can detour around the casparian strip and pass into the vascular cylinder |
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transport in the xylem |
endodermal cells and living cells within the vascular cylinder discharge water and minerals into their walls. The xylem vessels then transport water and minerals by bulk flow upward into shoot system |
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transpiration |
water vapor diffuses from moist air spaces of leaf to drier air outside via stomata. Water vapor lost is replaced by evaporation from water film that coats mesophyll cells. Evaporation of water film causes the air water interface to retreat farther into the cell wall and become more curved. this increases the surface tension and rate or transpiration. Water from xylem is pulled into surround cells and air spaces to replace water lost |
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xylem |
vascular tissue that conducts water and dissolved nutrients upward from root and also helps to form woody element of stem. |
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sugar source |
leaf site of production or storage photosynthesis |
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sugar sink |
flower site of consumption or storage cellular respiration |
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sucrose manufactured in mesophyll |
can travel via symplast to sieve tube elects. in some species, sucrose exits symplast near sieve tubes and travel through apoplast. it is then actively accumulated from apoplast by sieve-tube elements and their companion cells |
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chemiosmotic mechanism |
responsible for the active transport of sucrose into companion cells and sieve-tube elements. Proton pumps generate an H+ gradient, which drives sucrose accumulation with the help of a cotransport protein that couples sucrose transport to the diffusion of H+ back into the cell |
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Bulk flow by positive pressure in a sieve tube (bulk flow: pressure flow hypothesis) |
loading of sugar into sieve tube at source reduces water potential inside. this causes the tube to take up water by osmosis. This generates pressure that forces sap to flow along tube. The pressure is relieved by the unloading of sugar and the loss of water at the sink. In leaf-to-root translocation, xylem recycles water from sink to source |
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double circulation in frogs and other amphibians |
three chambers two atria and one ventricle. ridge within ventricle diverts most of oxygen rich blood from left atrium into systemic circuit and most of oxygen poor blood from right atrium into pulmocutaneous circuit. When under water the incomplete division of ventricle allows frog to adjust its circulation, shutting off most blood flow to its temporally ineffective lungs. blood flow continues to skin. oxygen poor and oxygen rich blood is mixed in ventricle |
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turtle,snakes, and lizards |
three chambered heart incomplete septum partially divides single ventricle into separate right and left chambers. Two major arteries called aortas lead to systemic circulation. Enables control of the relative amount of blood flowing to lungs and rest of body |
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mammals |
heart has two atria and two completely divided ventricles. left side receives and pumps only oxygen rich blood while the right side receives and pumps only oxygen poor blood. cannot vary blood flow to lungs without varying it throughout the body. |
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mammalian circulation (pulmonary circuit) |
contraction of right ventricle pumps blood to lungs via pulmonary arteries. Blood flows through capillary beds in left and right lungs, it loads O2 and unloads CO2. oxygen rich blood returns from lungs via pulmonary veins to the left atrium. Oxygen rich blood flows into left ventricle which pumps the blood out of body tissues through systemic circuit |
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mammalian circulation (systemic circuit) |
blood leaves left ventricle via the aorta which conveys blood to arteries leading throughout body. The first branches leading from aorta are the coronary arteries which supply blood to heart itself. Then branches lead to capillary beds in head and arms. The aorta the descends into abdomen supplying blood to arteries leading to capillary beds in abdominal organs and legs. Within capillaries there is a net diffusion of O2 from blood to tissues and CO2 into the blood. Capillaries rejoin forming venues which convey blood to wins. Oxygen poor blood from head, neck, and limbs is channeled into the superior vena cava. the inferior vena cava drains blood from trunk and hind limbs. The two cave empty their blood into the right atrium form which oxygen poor blood flows into right ventricle |
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contraction of heart |
it pumps blood |
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relaxation of heart |
chambers fill with blood |
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cardiac cycle |
one complete sequence of pumping and filling |
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systole |
the contraction phase of the cycle |
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diastole |
the relaxation phase of the cycle |
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cardiac output |
the volume of blood each ventricle pumps per minute depends on heart rate and stroke volume |
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heart rate |
rate of contraction or number of beats |
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stroke volume |
amount of blood pumped by ventricle in single contraction |
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Phase 1: atrial and ventricular diastole |
during a relaxation phase, blood returning from large veins flows into atria and then into ventricles through AV valves |
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Phase 2: atrial systole and ventricular diastole |
a brief period of atrial contraction then forces blood remaining in atria to ventricle |
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Phase 3: ventricular systole and atrial diastole |
during remainder of cycle, ventricular contraction pumps blood into large arteries through the semilunar valves |
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atrioventricular valve |
lies between each atrium and ventricle. anchored by strong fibers that prevent them from turning inside out. Pressure generated by powerful contraction of ventricles close AV valve, keeping blood form flowing back into heart |
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semilunar valves |
located at the two exits of heart: where aorta leaves left ventricle and where pulmonary artery leaves right ventricle. are pushed open by the pressure generated during contraction of ventricles. When ventricle relax, blood pressure built up in aorta and pulmonary artery closes the semilunar valves and prevents significant back flow |
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Sinoatrial node (SA) |
simultaneous contraction of atria |
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atrioventricular node (AV) |
simultaneous contraction of ventricles |
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endothelium |
line the central lumen of blood vessels. a single layer of flattened epithelial cells. smooth surface minimizes resistance to flow of blood. |
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capillaries |
smallest blood vessels. very thin walls that consist just of endothelium surrounding extracellular layer of basal lamina. The exchange of substances between blood and interstitial fluid occurs only in capillaries because walls are thin enough to permit exchange |
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arteries |
two layers of tissue surrounding the endothelium. Outer layer is formed by connect tissue that contains elastic fibers which allow them to stretch. the next layer contains smooth muscle and more elastic fibers. thick, strong walls, because of blood pumped at high pressures |
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veins |
two layers of tissue surrounding the endothelium. Outer layer is formed by connect tissue that contains elastic fibers which allow them to stretch. the next layer contains smooth muscle and more elastic fibers. thinner walls than arteries. contain valves that maintain a unidirectional flow of blood despite lower blood pressure
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How is blood flow in capillary beds altered? |
constriction or dilation of arterioles that supply capillary beds. Pre capillary sphincters, or rings of smooth muscle located at the entrance to capillary beds open and close to regulate and redirect the passage of blood into particular sets of capillaries. |
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Requirements for gas exchange |
gasexchange can only occur across a moist cell membrane.
gasesmust be in solution. supplyingmoisture to the respiratory surface. (blood supplies moisture) respiratorysurface must be shielded from drying out. (shielded by thoracic cavity andlimit where air is coming in and in plants shielded by cuticle and upper andlower epidermis) respiratorysurface must be of adequate dimensions. a wayto get gases to the respiratory surface without drying out the respiratorysurface. (sinuses and mouth help tomoisturize the air and in plants the stomata and guard cells help to regulateit) |
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bacteria and protists |
conditions are met by the environment in which they live |
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flat, 2 dimensional organisms |
usuallyaquatic and conditions are met by the environment they live in. The respiratorysystem is their skin but being flat allows them to maximize the area for gasintake.
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3 dimensional organisms |
need various adaptions to meet conditions. Includes plants |
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gills |
increase surface are |
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ventilation |
movement of respiratory medium over respiratory surface maintains partial pressure gradients of O2 and CO2 across gill that are necessary from gas exchange. The movement of gills through water by allowing a current of water to enter the mouth, pass through slits in pharynx, flows over gills and exits body |
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countercurrent exchange |
efficiency of gas exchange is maximized. the exchange of a substance or heat between two funds flowing in opposite directions. Fish gill is blood and water. Blood flows in direction opposite of water passing over gills and blood is less saturated with O2 than water it meets. This causes the transfer of O2 because partial gradient favors the diffusion of O2 from water to blood along the entire capillary. Very efficient |
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tracheal system |
insect. a network of air tubes that branch throughout the body. largest tubes, tracheae, open to outside. finest branches extend close to surface nearly every cell, where gas is exchanged by diffusion across the moist epithelium that lines the tips of the tracheal branches. The tracheal system brings air short distances to every body cell it can transport O1 and CO1 without the participation of the open circulatory system. Efficient form small insects but larger ones rely on movements that compress and expand the air tubes |
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lungs |
localized respiratory organs that are inholdings of the body surface and subdivided into numbers pockets. in mammals a system of branching ducts convey air to lungs in the thoracic cavity |
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Nasal cavity |
air enters nostrils and filtered by hairs, warmed humidified and sampled for odors as it flows through spaces in nasal cavity and leads to the pharynx where air and food cross |
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larynx |
upper part of the respiratory tract moves upward and tips the epiglottis over the glottis when food is swallowed closing off the trachea and allowing food to go down the esophagus to stomach. voice box |
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trachea |
windpipe. glottis is usually open to enable breathing. cartilage reinforces the walls of larynx and trachea to keep airway open. |
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bronchi |
the trachea branches into two bronchi, one leading to each lung. then each bronchi branch into finer tubes called bronchioles. the whole system is like a tree covered by cilia and thin film of mucus. mucus traps andy impurity while the beating cilia move mucus upward to the pharynx where it can be swallowed into the esphagus |
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alveoli |
gas exchange occurs here. air sacs clustered at the tips of the tiniest bronchioles. Human lungs contain millions. Oxygen in the air entering alveoli dissolves in the moist film lining their inner surfaces and rapidly diffuses across the epithelium into a web of capillaries that surrounds each alveolus. Net diffusion of carbon dioxide occurs in opposite direction from capillaries across the epithelium of the alveolus and into the air space. Highly susceptible to contamination |
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surfactant |
alveoli don't collapse under high surface tension because they produce a mixture of phospholipids and proteins for surface active agent, which coats the alveoli and reduces surface tension |
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coordination of circulation and gas exchange (pulmonary circuit) |
during inhalation fresh air mixes with air remaining in lungs. the result in mixture formed in alveoli has a higher PO2 and a lower PCO2 than blood flowing through alveolar capillaries. There is net diffusion of O2 down its partial pressure gradient from the air in alveoli to the blood. Co2 in blood undergoes net diffusion into air in alveoli. by the time blood leaves lungs in pulmonary veins its PO2 and PCO2 match values for those gases in alveoli. After returning to heat, blood is pumped through systemic circuit |
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coordination of circulation of gas exchange (systemic circuit) |
in systemic capillaries, gradients of partial pressure favor the net diffusion of O2 out of blood and CO2 into blood. these exist because cellular respiration in mitochondria of cells near each capillary removes O2 from and adds CO2 to the surrounding interstitial fluid. After blood unloads O2 and loads COs it is returned to heart and pumped back to lungs. There, exchange occurs across the alveolar capillaries resulting in exhaled air enriched in Co2 and partially depleted O2 |
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Bohr shift |
hemoglobins's oxygen binding affinity is inversely related to both the acidity and the concentration of carbon dioxide |
